SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c88db8cb463229c819650fa66ac072d223224c7ba3c70e96d1f6a39378cbf91e' 
  AND token = 'fxoYhOIWdF6TIyGDJm+YCwvmUygtvhQlIj+eCRuI77Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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