SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cf9dee9db62eabc970131b01038772ea955d76d85427ee0f6a330dbefc5cf30' 
  AND token = '6xaTctlBnU8uyrtdDbX4rjJ0nvL3tWa+7yBI+h6PvtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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