SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '530f05d784dfed09990a7248133c04b179065bbf49ae8208eaf5b648971e7310' 
  AND token = 'mcvdK/B5AjXrzzvM+Fh284xZpRegLWnO8K3GHgmYskk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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