SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b771b4ded1445dc7f5219e5a800bb0648567f9a8c8775d4d32eab90d26bd7ae9' 
  AND token = '7+ZoaqvzruX5tWijPJIv3ZEVFYsK/5mJhDKrdj52BCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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