SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0c896d7b448326b5dccb629bbf554411cda336d4167ea5ad3636df9df33305f' 
  AND token = 'gMBzCW1KC8WFjKvQ70og09Zoyoq+USJeoMf/SzwCL2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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