SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '379e78cef1f2148a3886c6573b4468c2df97eceab62f270b76317d498f85f03f' 
  AND token = '7+aLqTxOoNhmRJdY4fRYahDyDrEYaOxd1ta8GPA7nvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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