SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7aef24af8c26b85360d58207c1589a24c06a0f2b3294e1f9eeefd06d050e9cfe' 
  AND token = 'RHvmlRp8XwWRSyGcFpkYySiiZacmLUCTGtWv950lK7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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