SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36893c9245ee4bf045cd2abcf8983ed87a1b34342629ff03922874b89184de1a' 
  AND token = 'x0MtTT2dHPxyBQ1KCtxTMqygPe0mN9hRrUU1LuUQVNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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