SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09701665b284d42f10c7488a3688580d322d435d569bfd5717fdcb11fa976de1' 
  AND token = '8TqL0qpQYAiBI4+5ctZ5VLcj8wqtw9OurprOnchrIfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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