SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5df9b02aca1f0aaef02ac1ab6134823f4a660851b3e603a9a279d5bb762fec34' 
  AND token = 'jzPCVcFhJDEN2+R8Mlmg89CkuqvvBZXwSvssTV9KuqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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