SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f615cff823f2d2600f8e70219b454eef4b82dad4f5289b21596df1571b69222' 
  AND token = 'D8axwoa3go+uuOEDrphYSD5zhcnKlTjUvodstAGyOGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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