SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3c853b0ac977f29a74a1ffb1d2806f4a4be0cb5517bcc240604156b44edd917' 
  AND token = 'ZdNFWnPJWsVFvxc0cWvooEjl/zKa4UCtI8h683tnVrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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