SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15f732521be76d1e25e3d515fb858bc09148cd57a29b08ac1165442a79b2fb1c' 
  AND token = 'ky9eluCKmjKcfFE9wlYg6yFCQrhPwNgUZYnr8EPlqbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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