SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a385547c152a3c20e4e4fde041a5742256b25236266036d8e31f85c20fb40a09' 
  AND token = 'ILoBo3252zUtOr1eOdah72e8tsk3xrmt6KIJXadutwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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