SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5747a0baa4adaf8dbce15e4263d8ca183c30ab276ff932e9af38136d205d3621' 
  AND token = 'Rnbt+RTl+lNlZbicaCJewDRCQcgg22RbHIwdSDP+DXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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