SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85cebce78ad96105ec23cb061ca0d46af4eebf4e213bcdcf4e007fb77da9f4ef' 
  AND token = 'VC2gpUhqTSuzNEc8bgHTIBUIiWN+1NJnNcrHFpIG5Ok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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