SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bb7874afe2f77ddb03986a6c9ebc0612898df36aa82b2fd097c6aa0f6016125' 
  AND token = 'xG0QhDUmBUmQxXcff7KyJK6OqzPlFl+QK0a6QyNbXPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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