SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f56076a75cb82c9de58f23dd7002be2fd3b1cc1f3ff3b3a3d2fc56ce7a6882a2' 
  AND token = 'IFYoEFk/ds3fj6avVhW/xI0bNKOHZtU2Kv75Sq++1BU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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