SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0468cf7feacc6464fc0f089304ad20ff1234ff9dbffc70f0f54c4ffb28535763' 
  AND token = 'SuXmbSl7A4Ptz9MRlp2gvfQk6Rh/aXCsX+HaNjjylkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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