SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e06462f53ae3e46651214e067e495c8e549257752ea7f05e874e3b4b58ac922d' 
  AND token = 'ZQ8prkJWlTWfNO3bpCf1vXjkP/bRA/qaZsx8zvf3WpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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