SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68597b3bd1042431a4dd3b7c9b5ba190f0a3301261bc9358d423ee67397f32e4' 
  AND token = 'EWBjKR9RiyC+61X0utwjT9Sv1DCVt+v6GGIrubLxjss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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