SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd793ee7587989a1cbe06c00120428d04db11c161bdc551fd78aa1d5bc5fb0d2c' 
  AND token = '9xjrMwukJ7XljFrgdWII47YoolFPhQVKQzN6EfH7eKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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