SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b79e9011f3a0076a25a399d42bdb9ad385630655469b5b53f381989c5f00e3d6' 
  AND token = 'S1mwP51Z0J5oVdku7usaGY0k9CyF6nPexbcKDmvtOog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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