SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1277a66810e51e5a5a6563b3119509b66773ed3cae4fc7238b583aebbf48f52' 
  AND token = 'PvW7qi346xknJ7h2ilOpANrGPa1VFtFwGjzBNcKhJGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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