SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4fccaaac2692a471df7a232d07de1fbe3b211da4b0c100d5f25087578c08fa8' 
  AND token = 'TjUgsvPYY22hbKV1R0uKSNS6c51J9anIi93NvoKyun8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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