SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8fb44a30310bc46b12496cced9cca3c2e936bd9901c39015285efefa61361634' 
  AND token = 'wkAn7SCaW9SggHTKWoBWkE+EczNaU6AL0Q8GwHdiEV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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