SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c5cf615334abe257909992ffbb375872cf104102a4cdf7b26cbeed88dbf2228' 
  AND token = 'DdXHnSRMXXK2KlgglxEj46onBFETiAMXm/sIJVvCh78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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