SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43685e813730067a9e5b7811a4930ab59833bf60067f7d4bdbf0d214b2646ceb' 
  AND token = 'pSwYuGL86+wCTqzX50jSFkHPgxTvsv1dwQXfY7qmTFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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