SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '523cd80f6d2142fb55ef692915b95ec7b832e9e8a099b0bfcddb35c8163d43f9' 
  AND token = 'CyBpdG/ZglV1cw7ZI5qPa0ScnQO1+CJxXG1bJD9LVGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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