SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c86312015d6030d9da6e3918c3c44c29f4c4e542e720df292adf00c3f41ab336' 
  AND token = 'RY+dOjmwOufZ9R6GseMFdxomtkxxwGcrcjA2zWJ2hQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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