SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4386d1c47a9f860dec22f49f1530d3bbfde23c084beb010a2e4218aabdb4f70c' 
  AND token = 'rev8rR3gPwK60FN0dfu4726O+xPDZYrwdqpUpxwHmCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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