SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '337a3dadfa11fce59875524c550e43cecd0ddb8d6f2c0591df135e83553367f7' 
  AND token = 'mlh++lI8jVaX8LgaiaKit5PBoLwBIXD9mzM9IinU+H8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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