SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e735cf3a9aed5ad8dd2f27010c39d1a41c52f11ff9121cdda82f6ef48d1b66c' 
  AND token = 'tsMMuL0EyEJGJTrUEgi9MScZz05assR1xxGUdqPeke0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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