SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82434f34d827cbe7ce4fb183b715d1bcf3ce4fb5d4c429e03d42128513aa51c7' 
  AND token = 'QwM34fcmv7aFMFn9JIN6LYvDtn2pRjfpQwEkc0dAW78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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