SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b2688047571cecc77b67be2bbd61736a39453fc52ebcb11b50e566ad0abdacf' 
  AND token = 'ZsTzgkOYuuF2cyXPjX+AAQlNsRECqKvpXuQZI8KjgT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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