SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c57d0b3b61fe9cc101af85db1231ef8fa7a081156828af73c6c31b431657778' 
  AND token = 'S+ySkTHd6Eros9kdZMAKWVhE3x03qU4+kwldquu0IDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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