SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4899b3ccd248ee84bbfb2bdc4bb391777de632e03166a0d0ee4c98a308254e7' 
  AND token = 'A6LKx+aq2USAgvgcOIpgqzpKstU1rGWRVMjnAdajuYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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