SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f5c6aa4aaf881d37477e53236bd9815723865a2c31497422170bb49b55fd468' 
  AND token = 'uXNmsBVQI1ohqMrC6rLr0wLLh9zJu2SaMgSlPKgVjM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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