SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '068b1ae905c0b646f6ed324ad785b883a83c3d69fba471ae4054e68dbf07d618' 
  AND token = 'NRDhw8jzXcDEOnwpkoDYuYnpFIf5SXIne7pPcyO1OS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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