SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '91c286848db602594ed4577ddaf169ddeb641502c607e6cceb9ade9a1055ffa8' 
  AND token = 'dmjLNOcD44BLJX6dnwoH01HAGAB7aba1xQEXh938RtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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