SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67742ce1308319b0f5307717839dea4de9c3797b8a1b34558494be4e314ec35d' 
  AND token = 'mYA7uwYgDbty0R4BqxmIg94HX/v66WEbL4ARnDmFqDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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