SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37a83c61d89664031dfca19b5a000839c378a5e6b717acc3c2d98c98824dc0c6' 
  AND token = '2qP4V5raq2Gdk9IBA/DZ7Tkr/lfgOSQj/41K5wFoHak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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