SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83ddcdd587a6d0f3a179f4bfec15b5208853a3a9c18bd115663e1b817166ab61' 
  AND token = 'sbw1UfHyWsSCwJMJlKSXZOZNtWv5Ge57+XRSyGrohh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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