SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46203a8eb1ddb582536b52bb9b35d9a6a91838e891557f99cb35156e78a6fe1c' 
  AND token = 'AiY6vtMDSo6sRihyhif740WTxWdsKzDMQlVH0741Icg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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