SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e40164ee3364240f9168103886ea41c369d6ab9c9e52476786056914d6716ea' 
  AND token = 'xmkm+NdAYmGqV9zsKCjnJ9Kzit9D/zYKIwPtKGHkvcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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