SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12cf28834825cac2861ffaf21495b759814f50cedf47195a9c57cac3a7b739af' 
  AND token = 'JHTzMEBu9gX4X25LI9UFNwk2HxVXK/WFs+J8VFQ+6Cw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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