SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de09b763c40dc4b50ef030ba2132e7dc70379ec6e19b47cabd8c805bca08f01f' 
  AND token = 'AP7EJ9zWmHkzTOFY5XRmZGmvXkIX2bP9jJbn6YEqWt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}