SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ed18914eedca2efe8db4a3326a912d9cf3de7c6feee2ebb934dc786135f93e9' 
  AND token = 'p3nXyKBHb9ADT8W1C5GE+mHcu3+VhVclpzVVjZgkoN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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