SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '397a432ecfe043a56f02abb1d976dceee54cee66f20c40ddfe4d458150f3a871' 
  AND token = 'JPiDxcFmPh8kWTcv9Ls8zsPE47VJsQqiqqMl3xCh9g4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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