SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '10c39250219c42ccbc7b2306681b7fb660cc6282df974cf5e5c02ab4d93eafbc' 
  AND token = 'c79Gx+wq/JnL8R+Fx1ZMHfjJwioQc6vADquXLqR6+lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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