SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e0f626eda9b4e14ab18af86315750612368ddfb75a03c6aebe52189947df1b5' 
  AND token = '8hN2LD3uDOZXl3B+6jf0XmJdkghWVjJunY8J+U0p+cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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