SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f818e6c02efacd559b5c4c188967c8aff6e83cb333e617740ad8bd1f36dcb046' 
  AND token = 'pvd2V1Tgzcmw7AUJFl18fLcepLrHAmqEoWjwueHUwkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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