SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c35e957e279b627574f00af7d99126d9f29a87ef49391e66ea828cc12c78cc97' 
  AND token = 'C/3WDB0sY+ThHEuc5GcwtzgCQFDeDmMjOvMjZdMVdFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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