SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f369aab186a6402924a01a4fd37308a90614c7bef9d79d5ce1318f9073582abc' 
  AND token = 'yFcMxeLe3oDy8+ZhjUJJOx0wkIHNHEfjQdBAzssfWeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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