SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '731483fafbc36f965b719a2d4c04014c38cf6ad87d7dd86dc6d3eb26ae4708c5' 
  AND token = 'SMgQ4xxPkP4VU4KXaXENKDbMBOKZnCH3OWYjkiNpqzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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