SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '946381e45b154156d3382b42e9c715455dac0a980302f16c0d6dce8b40258b4d' 
  AND token = '1bcfFccibid2PNtAINCo+xwXJJteYZcSdpisxW2KAIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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