SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '628229475ec1c713800419a0cbf4385e1c4b9c2f8573b7e89713c96221abddc0' 
  AND token = 'J0+0i8JRkzz54PJlvZs05HGZfvhKeqRmYBU/1oSrVmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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