SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd99c3fcc32ba827befc5206f98d42f11262188f03b05e119fcd9dfb1b39c89ad' 
  AND token = 'cHxsavDWEVMYlrhCiazYO7bHvbL479/JXuAn0cyCEkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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