SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb35d495c6283d1448e2a8e19d9944b4fddc70cd34636b005ba46802b0d35278' 
  AND token = 'U6A8bBOM3i4pAyJsOO0+HJVTyNlZ65MLijQIHlBtWzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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