SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '387a4626db69e689b546124a63a207d1cdea1922c5f4d4d2a7f980c8dfa92671' 
  AND token = 'K9086bn2qh+HmZAfBYWhGbsGxKBw+qT9YuRwpH4UfZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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