SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5799376b81f50938dbc37709d75de66f1d1fb82cd08482ff1e67aaedf65b3044' 
  AND token = 'gxKBfToilvwKZH+D+bwoJayJxwPbUGLMp+P19M3MAk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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