SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52600817da7f0252390fc97801d409a22f559be731495b391883b6bd99ad6a6d' 
  AND token = 'aRHW00CP71GQNnZO9UgKT+aQZ/9+P9j65bs6feXyoQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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