SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c12eb5e1a7d6ac43d2efbd7cff74d40a4fa8d8767f4db740572bc96dfe9447ed' 
  AND token = 'quwjzdYB9+ddms/QgZKFU5/BpT2rZJFQw4FRPNJV/1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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