SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d6d7750592dfb0fd4f107bd638cca68361a221a8c50574f8691791f0d1b2f4d' 
  AND token = 'wkYaKP0RxyPKGhL+xUs4svSZH2FKF93XHvizmechX0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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