SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cc8ae1432614ac7f01c3123b9873d3596cd083d778a5e5441fbf61e00d2d842' 
  AND token = '/7hgSmiaaa+DD3qZXFjqs0hve71n8TWuy73+4hzkD2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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