SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9f9b8d16004fc3273b6b9600d1285c7d6e963921a0166168aceed889dcfc390' 
  AND token = 'o9B2x7YhqlFIz0X78F/XDKVhWqMJqx4guYsn2LZWm+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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