SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed1e3b18908d225020d28f47b581612016a958c97e4d3ee626497be1c6d2be3a' 
  AND token = 'LfVRjfU1aY1d146k5QwWQKFyTG6LK+9hUVTJxAtBGpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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