SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1857758673f2370c05c7493524a5f3290864fbc18999f938d315a70ca884c340' 
  AND token = 'eNdclNvxaDJ33lInE6qJO6d5RGV1d6J6XSGS29T5+kA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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