SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10f19f5fb5225c7a6dd49c69a2cf093a023a35c3085c01861388d56613f00451' 
  AND token = 'WD4502zxfNlnbOAmQG7jSAu6AbpX28dti8Cjkte2QOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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