SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '632a198916b6e394d51fa9039c1dd05375c3b7fa2d57f4524b18804ea45f7f56' 
  AND token = 'y2kdymDAS1spI6cnmzXJB5+OiuKeXRIJvpJhuCw66Og=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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