SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdbdefe32da77f59a20a34c2c29100853af85e5ca3811b401f537d6e98e365df' 
  AND token = 'xp15eaTBbKyrDTLhDhLpM//Kb3IaoY6geEkXZ0hMncI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}