SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c91b3fcebad37b605b46add27a320270115feb94703d8663605039b4ebd91c1' 
  AND token = 'ihH91//HOa3aIzOdh9xoc7Bl+7cZleYEilUSfWzBkC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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