SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a917f34f930eead652ff247cdc81d7686ad529f311dec1f53c0ed153da841203' 
  AND token = 'KRtPThhM/aPPAOz1qUNLOyw9Zjjk91TabEj8hGd2O1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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