SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43b1e43209471342ae6f4fae8efccb31480c04c660d78ed8bb2331c610ae591b' 
  AND token = 'JtrEGteKy2A3MS4iAS3K3VJQrYffz48eKvlAbS8Lz1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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