SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1478f867f51969efc459a27159e525bf6b3578347fa839e518b328404bda67d3' 
  AND token = 'Wrt1d8rLGrZrJpVFKwAxB6M5EOZ+9yIZlD2/flgqR5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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