SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f02aa77913d436a12023a41c94313a76afc2135a42715061b3ad7f5c84ded85' 
  AND token = 'zXqIRuLyEJPe/SnUsMZD/s5vs34xdWHN+FiKDgY5TI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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