SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f8ea6cff2548204555240abcab8652da1d7c0b2ce3d7fe6a3a16e4931c93894' 
  AND token = 'aX4MjmSCW/Wwi32x7PzhqNIvceROLwrB/wbYvC+BP3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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