SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3960b22c300eba85166b0e3967bb618d75bbd431b5aad02a18fc4fab083fef04' 
  AND token = 'CyqMkEjc9tcfmiGZXv6FpE7OE3gnczG+n6mD7lMCVTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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