SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2424f276ffb496a95fadcd942e2e33d4c809723243d76735ca03da38be28cfb1' 
  AND token = 'UZmP0r9CMbbBDi8BVvPGVwky5ZODoE/w8kL8N+1gq7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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