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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18d5536c4a20f198e29c24d6d1fbb3f2b1d21c0ae1fea93ed25db0cc5cbcf362' 
  AND token = 'Duk+xI9olEw7SEXL5JbPjzckTIJnqzHQ9qu5xNgf2ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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