SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63b358dcfac497fe779bcaf140b304dd1d5e9cb6f00d3a26dd245ca76c6f54ea' 
  AND token = 'TosKJDQEXDjA4h2PYJ6FgVZk5y+O22xTPYm1+aXGgls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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