SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4526aa470b517d49252bb977d321eeb75ce17d1cf73485ecc2ef7757e55b2a33' 
  AND token = 'f97whPGB8jvT0sDX5l6MI67TcJPC81JVxyQnBkCgdDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}