SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0c8eb474dc81dcf2b6e781694da4ba775bd2d1ea86190e850761fc756374f65' 
  AND token = 'BjNfIleDFIlSGrzxRCgWG7BoIq5rD6qdZeHghKenYnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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