SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d77b9204f243f2e7d1a1b6f9bde4e7e4c22d06c16305b69e27a1b3329f81517' 
  AND token = 'mCYpW3svB/CLGqRQuP0Xjt8OZpSnkTz1TWvdhb++bms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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