SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93bd52dcf42affe1dc9e614efbbbf4bd1dd007ebfe9b481ae02c318b9d53b16a' 
  AND token = 'QL+B4ttOuZRkf9BCsNnqGCP7taWRU6t3N+0HGqyjvDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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