SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b144f7a9d525bba07f735af81df6faf9579514844ff5171099441ffeef2ca726' 
  AND token = 'tK1EEt9XVTHTaW2k6mnAdMJZpWndPRXWFevehcI0yD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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