SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0577cb2c9ef8cb0f80f42ad55efc4c751e853702a1cadc425b0eaac79318ca68' 
  AND token = 'Z1fcmUyHZ/7kH8CfD9pJMV4HfffnjTmQvlGQ5MG2iw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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