SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb82ea70bdfe44b5625d0da6bdd87fa948fa4a817f4adeb280b5b67c8c428983' 
  AND token = '8ccdUz3DK67n7VOoMwJCVLrZNlTAAEwuxJW4d9MjKCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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