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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc3c6ba286c76d2afb4882d121b32fd04471355c34007f5a14cdadfa763afcc5' 
  AND token = '8t4hbKRrIgYGynnW2OsSFddKFqFVjBiziKBYDyt/Qa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}