SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc47fa015d6d311168a55d1293f98476f871018d82fe504878e9d5a81fd745d6' 
  AND token = 'YzgWnOljp1hApU/5vIPGcvQD268mZm+ceegP1n1FLfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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