SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5093ae33ecbdcaff5575c5b1fd7a9a4caffdd5dd0cb4ca665224c4867b85764' 
  AND token = 'Wgm+sByTQWlbIC+qqHxTULZWw8TDI08JCEqhyEvdi5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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