SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af2f781095b2c70cfbb496686383124b9c841286bd269705012197c09a0caccc' 
  AND token = 'a1Czpgspgb26v9objupqEh41L3/UteqsAyq5aVWerjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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