SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '863d477f3d3d0b4b4ae4f92e682666b707ccec5260cbd42c8585fc19e0862272' 
  AND token = 'seJhTx8rGmyta2mZwBJoYQsiGW3aN1VmD9alew/+7RI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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