SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37fe819a10ff9a612a5f57480bd2540641d92bad42b91b6a07c5a911901bd997' 
  AND token = 'kOkNyVl4pkBCC9ePPzCOYfjyolK/hzWCIwNixa9CgYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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