SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3751f04fa4f1a1b8b4e32ae5f43e867d0a111fdee580a1bf0606094dd99c605' 
  AND token = 'TOnZZYlGSjzqVgHKLBpxX0VyMHvQpY3d7zApf8dDOus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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