SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f825a0fe13a369e36bc9e972978935b6122ced74540036bf702d2a5813ef1ba' 
  AND token = 'dLYKhyVQEfRT9ggz2ZLtlyukyw1Jo1pxpb05Hv09s8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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