SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28cb7ce5de23054e2acffe0f666d24eda9d2c2e4a20ddc836ab7b79f389c6e9f' 
  AND token = 'GIggq/ChjzXcbKwaLSUHOca4QjL46QE7WKP+XgIpK6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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