SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12ab731f4bd48f150dd535f30270648de22da7474f2c8d95aebb84f226bdb750' 
  AND token = '7RKMIcdWl4hWtI5eoPtbSObTgpRApbD9mjd876ZeGn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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