SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7aa3823c64017451b214d5bd8c1d478cf571ee06c16e6cb79740d11ad2350631' 
  AND token = 'D7UgpC4FDYxHvf6IJOEB/I0VYAfbsc6thf19VBfMBD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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