SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1d90841941230e12cac56668f6111cd5cc8072b502a644b0084942a32f32f968' 
  AND token = 'VGbvuPIDNi5C+kJdeQX6YftO+uLiPfYX9JcrpPP5mlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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