SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85a8893acadcc6df27ebcf4432d58cc8b55d7797df07f1555b438f1cc4603e20' 
  AND token = 'AUCNqvDaq1ZIE4PRfCP9MX4rySVCS4fwZm5T+IOWVOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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