SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '246c3eef285cd851868e9a28c03eaa7cbb280224829441a76c5a09d1c66f5cfd' 
  AND token = '9vxp0AXTZONUiGbRO9sSo2zWMDHaPnvEfSHiFC2rEdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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