SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73178ae5e53133db6488183e263ee81bc1ce843e89310ea878935331454c8455' 
  AND token = 'NdgfHTpfeYc35y4HzQZimiZMk7TAnsZgm849D+/9jM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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