SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac14dfeea00c8f5cf6ea9966fdecdefd14d0a42cbd5e1dfde1c3c8fce5d23f3f' 
  AND token = 'Me8L9LPtxLx+fUrDHyuYonpkhwvid5WMOTAk0K69Fxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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