SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '834690cf739a245aad4ea34f32c9727cf506c2a728eb29dd515d8ce046ae18cf' 
  AND token = 'htASB1h3ILpKxgI5Z+Y3EzvYRTg8K3o1Chli2BIxWhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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