SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ec49b9a29c7ee5706db07562432c6d0fd9f3d4d7636557ef5d960b82cd3c45c' 
  AND token = 'BsFUFcwYgmmO0ctSjZEmTC+0F80qukXNTqhNUaBvzKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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