SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27afdadc1dc8fedbfc135ad3a62afbabd22eb888c75e6f5124de858c4e88bd16' 
  AND token = 'gQ83LoLc7FF1Sr1a0UwYM+eJsF3FBZduqUqhisJaxXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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