SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6c4df05c4634b6a3f2558b79a2764d443104dc2ffdb459e50887065f940d6a2f' 
  AND token = 'KGqbLmtHg2Bx2MdbhOeIHytz6qbqtuAxEfOwvLaplfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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