SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e7406ebe8c5987cf18145e048b8b9d3b706d02c95e05958b408708045b6b535' 
  AND token = 'sxQSSx74g1xFW9NXnonAScXXPmioFaSDqUixAlawxe4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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