SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02e3460a5553481e833490fe426066c7bb517c22785cf885da85b50c50397569' 
  AND token = 'BxzgBBUsODcXLP8TA6T4zj1qM6TOL5aOHfLHjWwmNX0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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