SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d753a28fc522bb836946f8b439b8f483357e60bda02f23f7da1f77cae30a969' 
  AND token = 'L53r+gd2jr+s0yCG1Da5zeJUBwWv8QQJP/xQFrbSsQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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