SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '373afc41deb31afbaa110ef562ab583a5d09edc3ffb67a912e76b4e5ec8c3b1e' 
  AND token = 'jXWxv8fl3XYo2rNOVtKdJwdblC21NqKtpQYhkF50mas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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