SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '885b6493d55ed42124204ef99eb9594bfc26187e0aa401ba7b48f68253f3d758' 
  AND token = 'jRRwq3fs/Xt8euQt+xSDD/rJEzzy/Tyly2GAh7KjnWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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