SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9048c210ac760e1370f342e6a793804e62a6a725e9dca5039e693b9549bb7293' 
  AND token = 'yJOHQViIxb+iGqeu8KrEv85JLf5rayS8TwzAKTKNUqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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