SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b31a54664828732e1039a319568a99ac75182c46df6e1f3088fd30e39639b253' 
  AND token = 'AJy0XJ3p0HMB+cAUwV3zs5/vf6gwb0jstlih1KB90wM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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