SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d34907519ebe8944b94200b629f516362b5d77b628b113d84e775fa9a03e954' 
  AND token = 'CUOQWOigmAVkOCF/EV1XckBjYsLmTiumZhhJkKJLIqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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