SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '289c0f5f5c275fee7c9ace418224a162063f244c63896bf03094f2575735e73b' 
  AND token = '6qL8YjTSRegKwfD1eQcqRyFJX+t83dxc/hXjSCdgPYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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