SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75ee9a35bd4554f549e380dce5c981787e337720fa66ea5339be88daaf4281ad' 
  AND token = 'Qwl7vGx3o40pveluKZdKvE7/BG3izXuDML+DjZcuVow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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