SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82d3d4365b62724658fc0b6199b82d39f0963354362fba1da663a0084dfe8b73' 
  AND token = 'F5lCQNopywyOF/14Y/A0ylppmW7V5VS4+qvBhK37lzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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