SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '739e4f95b353a3b849e6a0c2b564771d8bc9201342dcbc27831a4c0d2581b819' 
  AND token = 'pqnrELIVEzz89zYSe/zDfuKbgIdWvij8r1MhcI4yYFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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