SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a672cfa10d3552840b22f65d26443d4d434c3fef2d2ad31398eef9f308e8e5d' 
  AND token = '53LLRIKb1qnWBhkORvyfYhYYjAhJKlzBeI6SBjqsPzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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