SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dcc3298e957e9842fe8b2196a21c0668a7d0ef32704921526ddd33b57f2ff2a' 
  AND token = 'l58ltM/pCLbH0DD4ql+6Wiwizj4q+jrmWy04xwTGJsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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