SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be23e3f862c26f3209b0e01b945650c50d4066a7bfd97aacfdd4f7b18ea484fa' 
  AND token = 'a3XGV+zG3ZPwJONqr+xiRYAVhBAz/N5jV+SqcR6PdrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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