SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3420c8986d682064c8295ecc2efaa306010455c1e6c5070233d770ba2d8ab3f7' 
  AND token = 'BtNg4eqJIg6Ta1TQW03seINKsypjgdPmxw/K0M14Yms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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