SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '092ff5faf257bbc74414ecb493d07370b1d2fd36c7a9cd5dda1009e2fc7994b0' 
  AND token = 'WtPtnSiDihNzexBwmslBKER8D6Kh0/tsDwbpXVBqNR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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