SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83ab088ca2e1493f018028caf6424342db0360980085341462cc81ae3fa20826' 
  AND token = 'iBiASkL2pylsLeQa+awXWfpm9JPikwQo6ml5q7jbc40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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