SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63e41b998420b70a6f487307e588c02f486a468d508be83007e924a845475e85' 
  AND token = '6GXYkhm5XaDwTJdFi6T1H1SSNoSzaS55TvLcZpgbLzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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