SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33501d579e878d55a517f3099782bb63d61f75225d17fdf08221e1396d173697' 
  AND token = 'uDQFjjCp24PnMMClB0EduyJG3cznLXr5iaWAxLdMYto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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