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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcbcd4f3dcbda9ac727b26c7537edb6961c8cb26c931cc79fd21dc6b47f4be4f' 
  AND token = 'tj3AX02Zt49xvQu1aUTeW84zcgjFk5+32Lp9n31lOWs=' 
  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"
    }
  }
}