SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fe5e78db03ff0bab560311d09a98f612a2ffa5a7807939597472db3b42b44e0' 
  AND token = 'NkybHozoPKOq19km+/S0GZyqyxvVqSN8O5r4+WvdICw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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