SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c4b9a82603d836371d73c1ef9292c84d22a716e3bbcdd28583079be9e5fa9c6' 
  AND token = '0XmiK40mduNPWDdbQS8mqufWHKQcU2FFAZbKI3Yg7B4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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