SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '210590b621ae031471984eeb585c8a16716bbd9ab25820cc656e88e96392a2d1' 
  AND token = 'IxLuaSg96DnRgi2a26Naatyahe5iIBy4kf5USCteoFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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