SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dcdda3e19c70c8159a527c73b9e81c33e30016c22d50f040a6f00c52a073e41' 
  AND token = '4Rod/dbubSEefJNSzmFKmpGmfzY2CST1VKiD38s4xQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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