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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1a0c5b553d7102787cf7a3e3bf6dede8c8ee267ad7dd6b43c4d7136782148df' 
  AND token = 'Vblw530Qvgx6VhCBy0E9nmHIzn8UvulzEkgHkGNT18Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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