SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e1be120fc7aa8ed3f812bd4bd3c640440959aadd1414f42e266cc21faebeb4b' 
  AND token = 'fH+ujmr0xQQl7S3A5SNb9CwP7iaEgMTgijCharbxPuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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