SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4fcc838149dfd9281dbb6970eca70891de608466d2671282a64efa40cb656236' 
  AND token = '5rkwRE17lUSKd7IN1En1ewiKQkse01aUYo3cAQdkjI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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