SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4758271d30222e46f285e089f7d1c4b03a323ee118144bf16cc729a85e5e9aea' 
  AND token = 'WsPsVkolIh+ScegEC9o+0YIjHk5SbgzuZhzEJBbI6BQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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