SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de6b9494c470146059d763d7aff6628757b9a8bb048078589f70e9f168428bd5' 
  AND token = '/6WSnIP6FCv3LzgE7+yRlK9v8AfZ9RoagBh9FA1GeXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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