SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fcf0fa68c294a18f166561949cd656db29632325388e490f962e2b43ae33418' 
  AND token = 'SioGLv5BOtuthmyFqoOeJaGvZAYczsnfHwIidONKiPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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