SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dff6ad218e427111a8803e11ff2a8f1e0f823667dd674e1fd1daea679ac297a' 
  AND token = 'DNATmjgvZX5ZafVnoZEGyqyPX3sF/Y5prz/QUOYTyQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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