SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12e450fdb14483c85716e4dc592564a827af7d2324c5b3c38cba2961c2a524a7' 
  AND token = '3QiYUIqwrTyKUWTMDbeEwEd7Ri6Lhp2JChxebceFVOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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