SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2010bd342cc3a06c8dcde3814d33aa14c8a3a2b4c5e19e66b952554ea6f79be1' 
  AND token = 'q57ZjQdkhFhIkPZftRyKD//sl0gaapV+WElP3tBkUm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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