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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2037e5dfd312bb39661672044dcb8a2f5f7fd2f14cf28ee99993c8bb0107e5d' 
  AND token = 'JWvl4zyktcMRS1X6gP1c1SVe6IQ+/IJwyZTuedIYtBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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